As a parameter indicating the characteristics of a time-series signal such as an audio signal, a parameter such as LSP is known (see, for example, Non-patent Literature 1).
Since LSP consists of multiple values, there may be a case where it is difficult to use LSP directly for sound classification and segment estimation. For example, since the LSP consists of multiple values, it is not easy to perform processing based on a threshold value using LSP.
Incidentally, though not publicly known, the inventor has proposed a parameter η. This parameter η is a shape parameter that sets a probability distribution to which an object to be coded of arithmetic codes belongs in a coding system that performs arithmetic coding of the quantization value of a coefficient in a frequency domain using a linear prediction envelope such as that used in 3GPP Enhanced Voice Services (EVS), for example. The parameter η is relevant to the distribution of objects to be coded, and appropriate setting of the parameter η makes it possible to perform efficient coding and decoding.
Moreover, the parameter η can be an index indicating the characteristics of a time-series signal. Therefore, the parameter η can be used in a technology other than the above-described coding processing, for example, a speech sound-related technology such as a matching technology or a technology to judge the segment or type of a signal.
Furthermore, since the parameter η is a single value, processing based on a threshold value using the parameter η is easier than processing based on a threshold value using LSP. For this reason, the parameter η can be used easily in a speech sound-related technology such as a matching technology or a technology to judge the segment or type of a signal.